A method of measuring a pulse wave using an LED (Light Emitting Diode) that emits light toward a blood vessel and a photodiode that receives light transmitted through or reflected by the blood vessel is known. In this method, a signal output by a light receiving element corresponds to a pulse wave. However, this signal generally includes not just a pulse wave component but often also a low frequency noise component, such as a component due to ambient light fluctuations. Therefore, signal processing in which an HPF (High Pass Filter) is used to remove such a low frequency noise component is performed.
However, when significant low frequency noise must be removed through the HPF, it becomes necessary to perform complicated computations using lots of signal data to exclude this noise. Therefore, substantial time is spent in signal processing calculations, thus, power consumption and response time is increased as a result.